The antioxidant chemicals that make blueberries blue -- anthocyanins -- may also keep the brain healthy, according to research presented at the Successful Aging conference in June, 2001.
Other fruits and vegetables have this class of chemicals, but blueberries are the heavy hitters, said Barbara Shukitt-Hale of the U.S. Department of Agriculture Human Nutrition Research Center on Aging at Tufts University in Boston. Blackberries and boysenberries also have high levels.
Shukitt-Hale, and her colleague James Joseph, found that old rats whose nutritionally well balanced diet was supplemented with the human equivalent of half cup of blueberries a day for two months, were able to reverse age-related declines in the ability to do a motor task, hanging on to a rotating bar, and a mental task -- learning how to find a perch in small pool of water.
Shukitt-Hale said another class of chemicals in the berries, hydroxycinnamates are also important, and that it is very likely both classes of chemicals work together. "The whole is greater than the sum of its parts," she said.
Tests on human cells in test tubes found that the two classes of chemicals protected against the damage caused by free radicals, chemicals that are created during such normal processes as digestion. Many scientists regard this so-called oxidative damage as a cause of aging and age-linked damage to the body.
David Morgan, a pharmacologist at the University of South Florida, found that -- when fed blueberries -- mice genetically altered to have symptoms and brain changes similar to those in Alzheimer's disease showed improvement on some learning tasks as compared with mice not given the diet. Moreover, said Shukitt-Hale, an analysis of the brain tissue of these mice showed the structures in the brain involved in learning and memory were better able to communicate with one another.
It's too early to say for sure if blueberries can delay or prevent Alzheimer's disease, said Shukitt-Hale, "but you can't get hurt by trying. And they taste good, too."
Successful Aging Conference, Jun 2001